1. Field
The described technology relates generally to an organic light emitting diode display, and more particularly, to an organic light emitting diode display utilizing a refractive index.
2. Description of the Related Technology
Organic light emitting diode displays have a self emissive characteristic, and have a relatively small thickness and weight. Organic light emitting diode displays generally exhibit high quality characteristics such as low power consumption, high luminance, and short response time.
Organic light emitting diode displays generally include a first substrate with organic light emitting diodes, and a second substrate facing the first substrate to protect the organic light emitting diodes of the first substrate. The organic light emitting diode generally includes an organic emission layer, and first and second electrodes facing with the organic emission layer interposed therebetween.
Conventional organic light emitting diode displays may be classified as (1) top emission type, where the light emitted from the organic light emitting diode is illuminated to the second substrate, (2) bottom emission type, where the light emitted from the organic light emitting diode is illuminated to the first substrate, and (3) dual emission type, where the light emitted from the organic light emitting diode is illuminated to both the first and second substrates.
In top emission type displays, the first electrode is a reflective electrode and the second electrode is a semitransparent electrode. The top emission type displays comprise a micro-cavity structure.
It is generally challenging to manufacture large-sized top emission type organic light emitting diode displays. The challenge is related to the fact that the second electrode should be thin in order to be semitransparent, but as the second electrode is formed with one layer over the entire area of the organic light emitting diode, the surface resistivity thereof increases with the device enlargement, so that the current flow along the second electrode does not occur fluently.
It is thus generally preferable to use bottom emission type structures for larger displays, where the second electrode can be sufficiently thick.
Generally with bottom emission type displays, light emission efficiency and color reproduction are deteriorated.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.